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1/* SCTP kernel implementation
2 * (C) Copyright 2007 Hewlett-Packard Development Company, L.P.
3 *
4 * This file is part of the SCTP kernel implementation
5 *
6 * This SCTP implementation is free software;
7 * you can redistribute it and/or modify it under the terms of
8 * the GNU General Public License as published by
9 * the Free Software Foundation; either version 2, or (at your option)
10 * any later version.
11 *
12 * This SCTP implementation is distributed in the hope that it
13 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
14 * ************************
15 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
16 * See the GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with GNU CC; see the file COPYING. If not, see
20 * <http://www.gnu.org/licenses/>.
21 *
22 * Please send any bug reports or fixes you make to the
23 * email address(es):
24 * lksctp developers <linux-sctp@vger.kernel.org>
25 *
26 * Written or modified by:
27 * Vlad Yasevich <vladislav.yasevich@hp.com>
28 */
29
30#include <crypto/hash.h>
31#include <linux/slab.h>
32#include <linux/types.h>
33#include <linux/scatterlist.h>
34#include <net/sctp/sctp.h>
35#include <net/sctp/auth.h>
36
37static struct sctp_hmac sctp_hmac_list[SCTP_AUTH_NUM_HMACS] = {
38 {
39 /* id 0 is reserved. as all 0 */
40 .hmac_id = SCTP_AUTH_HMAC_ID_RESERVED_0,
41 },
42 {
43 .hmac_id = SCTP_AUTH_HMAC_ID_SHA1,
44 .hmac_name = "hmac(sha1)",
45 .hmac_len = SCTP_SHA1_SIG_SIZE,
46 },
47 {
48 /* id 2 is reserved as well */
49 .hmac_id = SCTP_AUTH_HMAC_ID_RESERVED_2,
50 },
51#if IS_ENABLED(CONFIG_CRYPTO_SHA256)
52 {
53 .hmac_id = SCTP_AUTH_HMAC_ID_SHA256,
54 .hmac_name = "hmac(sha256)",
55 .hmac_len = SCTP_SHA256_SIG_SIZE,
56 }
57#endif
58};
59
60
61void sctp_auth_key_put(struct sctp_auth_bytes *key)
62{
63 if (!key)
64 return;
65
66 if (refcount_dec_and_test(&key->refcnt)) {
67 kzfree(key);
68 SCTP_DBG_OBJCNT_DEC(keys);
69 }
70}
71
72/* Create a new key structure of a given length */
73static struct sctp_auth_bytes *sctp_auth_create_key(__u32 key_len, gfp_t gfp)
74{
75 struct sctp_auth_bytes *key;
76
77 /* Verify that we are not going to overflow INT_MAX */
78 if (key_len > (INT_MAX - sizeof(struct sctp_auth_bytes)))
79 return NULL;
80
81 /* Allocate the shared key */
82 key = kmalloc(sizeof(struct sctp_auth_bytes) + key_len, gfp);
83 if (!key)
84 return NULL;
85
86 key->len = key_len;
87 refcount_set(&key->refcnt, 1);
88 SCTP_DBG_OBJCNT_INC(keys);
89
90 return key;
91}
92
93/* Create a new shared key container with a give key id */
94struct sctp_shared_key *sctp_auth_shkey_create(__u16 key_id, gfp_t gfp)
95{
96 struct sctp_shared_key *new;
97
98 /* Allocate the shared key container */
99 new = kzalloc(sizeof(struct sctp_shared_key), gfp);
100 if (!new)
101 return NULL;
102
103 INIT_LIST_HEAD(&new->key_list);
104 refcount_set(&new->refcnt, 1);
105 new->key_id = key_id;
106
107 return new;
108}
109
110/* Free the shared key structure */
111static void sctp_auth_shkey_destroy(struct sctp_shared_key *sh_key)
112{
113 BUG_ON(!list_empty(&sh_key->key_list));
114 sctp_auth_key_put(sh_key->key);
115 sh_key->key = NULL;
116 kfree(sh_key);
117}
118
119void sctp_auth_shkey_release(struct sctp_shared_key *sh_key)
120{
121 if (refcount_dec_and_test(&sh_key->refcnt))
122 sctp_auth_shkey_destroy(sh_key);
123}
124
125void sctp_auth_shkey_hold(struct sctp_shared_key *sh_key)
126{
127 refcount_inc(&sh_key->refcnt);
128}
129
130/* Destroy the entire key list. This is done during the
131 * associon and endpoint free process.
132 */
133void sctp_auth_destroy_keys(struct list_head *keys)
134{
135 struct sctp_shared_key *ep_key;
136 struct sctp_shared_key *tmp;
137
138 if (list_empty(keys))
139 return;
140
141 key_for_each_safe(ep_key, tmp, keys) {
142 list_del_init(&ep_key->key_list);
143 sctp_auth_shkey_release(ep_key);
144 }
145}
146
147/* Compare two byte vectors as numbers. Return values
148 * are:
149 * 0 - vectors are equal
150 * < 0 - vector 1 is smaller than vector2
151 * > 0 - vector 1 is greater than vector2
152 *
153 * Algorithm is:
154 * This is performed by selecting the numerically smaller key vector...
155 * If the key vectors are equal as numbers but differ in length ...
156 * the shorter vector is considered smaller
157 *
158 * Examples (with small values):
159 * 000123456789 > 123456789 (first number is longer)
160 * 000123456789 < 234567891 (second number is larger numerically)
161 * 123456789 > 2345678 (first number is both larger & longer)
162 */
163static int sctp_auth_compare_vectors(struct sctp_auth_bytes *vector1,
164 struct sctp_auth_bytes *vector2)
165{
166 int diff;
167 int i;
168 const __u8 *longer;
169
170 diff = vector1->len - vector2->len;
171 if (diff) {
172 longer = (diff > 0) ? vector1->data : vector2->data;
173
174 /* Check to see if the longer number is
175 * lead-zero padded. If it is not, it
176 * is automatically larger numerically.
177 */
178 for (i = 0; i < abs(diff); i++) {
179 if (longer[i] != 0)
180 return diff;
181 }
182 }
183
184 /* lengths are the same, compare numbers */
185 return memcmp(vector1->data, vector2->data, vector1->len);
186}
187
188/*
189 * Create a key vector as described in SCTP-AUTH, Section 6.1
190 * The RANDOM parameter, the CHUNKS parameter and the HMAC-ALGO
191 * parameter sent by each endpoint are concatenated as byte vectors.
192 * These parameters include the parameter type, parameter length, and
193 * the parameter value, but padding is omitted; all padding MUST be
194 * removed from this concatenation before proceeding with further
195 * computation of keys. Parameters which were not sent are simply
196 * omitted from the concatenation process. The resulting two vectors
197 * are called the two key vectors.
198 */
199static struct sctp_auth_bytes *sctp_auth_make_key_vector(
200 struct sctp_random_param *random,
201 struct sctp_chunks_param *chunks,
202 struct sctp_hmac_algo_param *hmacs,
203 gfp_t gfp)
204{
205 struct sctp_auth_bytes *new;
206 __u32 len;
207 __u32 offset = 0;
208 __u16 random_len, hmacs_len, chunks_len = 0;
209
210 random_len = ntohs(random->param_hdr.length);
211 hmacs_len = ntohs(hmacs->param_hdr.length);
212 if (chunks)
213 chunks_len = ntohs(chunks->param_hdr.length);
214
215 len = random_len + hmacs_len + chunks_len;
216
217 new = sctp_auth_create_key(len, gfp);
218 if (!new)
219 return NULL;
220
221 memcpy(new->data, random, random_len);
222 offset += random_len;
223
224 if (chunks) {
225 memcpy(new->data + offset, chunks, chunks_len);
226 offset += chunks_len;
227 }
228
229 memcpy(new->data + offset, hmacs, hmacs_len);
230
231 return new;
232}
233
234
235/* Make a key vector based on our local parameters */
236static struct sctp_auth_bytes *sctp_auth_make_local_vector(
237 const struct sctp_association *asoc,
238 gfp_t gfp)
239{
240 return sctp_auth_make_key_vector(
241 (struct sctp_random_param *)asoc->c.auth_random,
242 (struct sctp_chunks_param *)asoc->c.auth_chunks,
243 (struct sctp_hmac_algo_param *)asoc->c.auth_hmacs, gfp);
244}
245
246/* Make a key vector based on peer's parameters */
247static struct sctp_auth_bytes *sctp_auth_make_peer_vector(
248 const struct sctp_association *asoc,
249 gfp_t gfp)
250{
251 return sctp_auth_make_key_vector(asoc->peer.peer_random,
252 asoc->peer.peer_chunks,
253 asoc->peer.peer_hmacs,
254 gfp);
255}
256
257
258/* Set the value of the association shared key base on the parameters
259 * given. The algorithm is:
260 * From the endpoint pair shared keys and the key vectors the
261 * association shared keys are computed. This is performed by selecting
262 * the numerically smaller key vector and concatenating it to the
263 * endpoint pair shared key, and then concatenating the numerically
264 * larger key vector to that. The result of the concatenation is the
265 * association shared key.
266 */
267static struct sctp_auth_bytes *sctp_auth_asoc_set_secret(
268 struct sctp_shared_key *ep_key,
269 struct sctp_auth_bytes *first_vector,
270 struct sctp_auth_bytes *last_vector,
271 gfp_t gfp)
272{
273 struct sctp_auth_bytes *secret;
274 __u32 offset = 0;
275 __u32 auth_len;
276
277 auth_len = first_vector->len + last_vector->len;
278 if (ep_key->key)
279 auth_len += ep_key->key->len;
280
281 secret = sctp_auth_create_key(auth_len, gfp);
282 if (!secret)
283 return NULL;
284
285 if (ep_key->key) {
286 memcpy(secret->data, ep_key->key->data, ep_key->key->len);
287 offset += ep_key->key->len;
288 }
289
290 memcpy(secret->data + offset, first_vector->data, first_vector->len);
291 offset += first_vector->len;
292
293 memcpy(secret->data + offset, last_vector->data, last_vector->len);
294
295 return secret;
296}
297
298/* Create an association shared key. Follow the algorithm
299 * described in SCTP-AUTH, Section 6.1
300 */
301static struct sctp_auth_bytes *sctp_auth_asoc_create_secret(
302 const struct sctp_association *asoc,
303 struct sctp_shared_key *ep_key,
304 gfp_t gfp)
305{
306 struct sctp_auth_bytes *local_key_vector;
307 struct sctp_auth_bytes *peer_key_vector;
308 struct sctp_auth_bytes *first_vector,
309 *last_vector;
310 struct sctp_auth_bytes *secret = NULL;
311 int cmp;
312
313
314 /* Now we need to build the key vectors
315 * SCTP-AUTH , Section 6.1
316 * The RANDOM parameter, the CHUNKS parameter and the HMAC-ALGO
317 * parameter sent by each endpoint are concatenated as byte vectors.
318 * These parameters include the parameter type, parameter length, and
319 * the parameter value, but padding is omitted; all padding MUST be
320 * removed from this concatenation before proceeding with further
321 * computation of keys. Parameters which were not sent are simply
322 * omitted from the concatenation process. The resulting two vectors
323 * are called the two key vectors.
324 */
325
326 local_key_vector = sctp_auth_make_local_vector(asoc, gfp);
327 peer_key_vector = sctp_auth_make_peer_vector(asoc, gfp);
328
329 if (!peer_key_vector || !local_key_vector)
330 goto out;
331
332 /* Figure out the order in which the key_vectors will be
333 * added to the endpoint shared key.
334 * SCTP-AUTH, Section 6.1:
335 * This is performed by selecting the numerically smaller key
336 * vector and concatenating it to the endpoint pair shared
337 * key, and then concatenating the numerically larger key
338 * vector to that. If the key vectors are equal as numbers
339 * but differ in length, then the concatenation order is the
340 * endpoint shared key, followed by the shorter key vector,
341 * followed by the longer key vector. Otherwise, the key
342 * vectors are identical, and may be concatenated to the
343 * endpoint pair key in any order.
344 */
345 cmp = sctp_auth_compare_vectors(local_key_vector,
346 peer_key_vector);
347 if (cmp < 0) {
348 first_vector = local_key_vector;
349 last_vector = peer_key_vector;
350 } else {
351 first_vector = peer_key_vector;
352 last_vector = local_key_vector;
353 }
354
355 secret = sctp_auth_asoc_set_secret(ep_key, first_vector, last_vector,
356 gfp);
357out:
358 sctp_auth_key_put(local_key_vector);
359 sctp_auth_key_put(peer_key_vector);
360
361 return secret;
362}
363
364/*
365 * Populate the association overlay list with the list
366 * from the endpoint.
367 */
368int sctp_auth_asoc_copy_shkeys(const struct sctp_endpoint *ep,
369 struct sctp_association *asoc,
370 gfp_t gfp)
371{
372 struct sctp_shared_key *sh_key;
373 struct sctp_shared_key *new;
374
375 BUG_ON(!list_empty(&asoc->endpoint_shared_keys));
376
377 key_for_each(sh_key, &ep->endpoint_shared_keys) {
378 new = sctp_auth_shkey_create(sh_key->key_id, gfp);
379 if (!new)
380 goto nomem;
381
382 new->key = sh_key->key;
383 sctp_auth_key_hold(new->key);
384 list_add(&new->key_list, &asoc->endpoint_shared_keys);
385 }
386
387 return 0;
388
389nomem:
390 sctp_auth_destroy_keys(&asoc->endpoint_shared_keys);
391 return -ENOMEM;
392}
393
394
395/* Public interface to create the association shared key.
396 * See code above for the algorithm.
397 */
398int sctp_auth_asoc_init_active_key(struct sctp_association *asoc, gfp_t gfp)
399{
400 struct sctp_auth_bytes *secret;
401 struct sctp_shared_key *ep_key;
402 struct sctp_chunk *chunk;
403
404 /* If we don't support AUTH, or peer is not capable
405 * we don't need to do anything.
406 */
407 if (!asoc->ep->auth_enable || !asoc->peer.auth_capable)
408 return 0;
409
410 /* If the key_id is non-zero and we couldn't find an
411 * endpoint pair shared key, we can't compute the
412 * secret.
413 * For key_id 0, endpoint pair shared key is a NULL key.
414 */
415 ep_key = sctp_auth_get_shkey(asoc, asoc->active_key_id);
416 BUG_ON(!ep_key);
417
418 secret = sctp_auth_asoc_create_secret(asoc, ep_key, gfp);
419 if (!secret)
420 return -ENOMEM;
421
422 sctp_auth_key_put(asoc->asoc_shared_key);
423 asoc->asoc_shared_key = secret;
424 asoc->shkey = ep_key;
425
426 /* Update send queue in case any chunk already in there now
427 * needs authenticating
428 */
429 list_for_each_entry(chunk, &asoc->outqueue.out_chunk_list, list) {
430 if (sctp_auth_send_cid(chunk->chunk_hdr->type, asoc)) {
431 chunk->auth = 1;
432 if (!chunk->shkey) {
433 chunk->shkey = asoc->shkey;
434 sctp_auth_shkey_hold(chunk->shkey);
435 }
436 }
437 }
438
439 return 0;
440}
441
442
443/* Find the endpoint pair shared key based on the key_id */
444struct sctp_shared_key *sctp_auth_get_shkey(
445 const struct sctp_association *asoc,
446 __u16 key_id)
447{
448 struct sctp_shared_key *key;
449
450 /* First search associations set of endpoint pair shared keys */
451 key_for_each(key, &asoc->endpoint_shared_keys) {
452 if (key->key_id == key_id) {
453 if (!key->deactivated)
454 return key;
455 break;
456 }
457 }
458
459 return NULL;
460}
461
462/*
463 * Initialize all the possible digest transforms that we can use. Right now
464 * now, the supported digests are SHA1 and SHA256. We do this here once
465 * because of the restrictiong that transforms may only be allocated in
466 * user context. This forces us to pre-allocated all possible transforms
467 * at the endpoint init time.
468 */
469int sctp_auth_init_hmacs(struct sctp_endpoint *ep, gfp_t gfp)
470{
471 struct crypto_shash *tfm = NULL;
472 __u16 id;
473
474 /* If AUTH extension is disabled, we are done */
475 if (!ep->auth_enable) {
476 ep->auth_hmacs = NULL;
477 return 0;
478 }
479
480 /* If the transforms are already allocated, we are done */
481 if (ep->auth_hmacs)
482 return 0;
483
484 /* Allocated the array of pointers to transorms */
485 ep->auth_hmacs = kzalloc(sizeof(struct crypto_shash *) *
486 SCTP_AUTH_NUM_HMACS, gfp);
487 if (!ep->auth_hmacs)
488 return -ENOMEM;
489
490 for (id = 0; id < SCTP_AUTH_NUM_HMACS; id++) {
491
492 /* See is we support the id. Supported IDs have name and
493 * length fields set, so that we can allocated and use
494 * them. We can safely just check for name, for without the
495 * name, we can't allocate the TFM.
496 */
497 if (!sctp_hmac_list[id].hmac_name)
498 continue;
499
500 /* If this TFM has been allocated, we are all set */
501 if (ep->auth_hmacs[id])
502 continue;
503
504 /* Allocate the ID */
505 tfm = crypto_alloc_shash(sctp_hmac_list[id].hmac_name, 0, 0);
506 if (IS_ERR(tfm))
507 goto out_err;
508
509 ep->auth_hmacs[id] = tfm;
510 }
511
512 return 0;
513
514out_err:
515 /* Clean up any successful allocations */
516 sctp_auth_destroy_hmacs(ep->auth_hmacs);
517 return -ENOMEM;
518}
519
520/* Destroy the hmac tfm array */
521void sctp_auth_destroy_hmacs(struct crypto_shash *auth_hmacs[])
522{
523 int i;
524
525 if (!auth_hmacs)
526 return;
527
528 for (i = 0; i < SCTP_AUTH_NUM_HMACS; i++) {
529 crypto_free_shash(auth_hmacs[i]);
530 }
531 kfree(auth_hmacs);
532}
533
534
535struct sctp_hmac *sctp_auth_get_hmac(__u16 hmac_id)
536{
537 return &sctp_hmac_list[hmac_id];
538}
539
540/* Get an hmac description information that we can use to build
541 * the AUTH chunk
542 */
543struct sctp_hmac *sctp_auth_asoc_get_hmac(const struct sctp_association *asoc)
544{
545 struct sctp_hmac_algo_param *hmacs;
546 __u16 n_elt;
547 __u16 id = 0;
548 int i;
549
550 /* If we have a default entry, use it */
551 if (asoc->default_hmac_id)
552 return &sctp_hmac_list[asoc->default_hmac_id];
553
554 /* Since we do not have a default entry, find the first entry
555 * we support and return that. Do not cache that id.
556 */
557 hmacs = asoc->peer.peer_hmacs;
558 if (!hmacs)
559 return NULL;
560
561 n_elt = (ntohs(hmacs->param_hdr.length) -
562 sizeof(struct sctp_paramhdr)) >> 1;
563 for (i = 0; i < n_elt; i++) {
564 id = ntohs(hmacs->hmac_ids[i]);
565
566 /* Check the id is in the supported range. And
567 * see if we support the id. Supported IDs have name and
568 * length fields set, so that we can allocate and use
569 * them. We can safely just check for name, for without the
570 * name, we can't allocate the TFM.
571 */
572 if (id > SCTP_AUTH_HMAC_ID_MAX ||
573 !sctp_hmac_list[id].hmac_name) {
574 id = 0;
575 continue;
576 }
577
578 break;
579 }
580
581 if (id == 0)
582 return NULL;
583
584 return &sctp_hmac_list[id];
585}
586
587static int __sctp_auth_find_hmacid(__be16 *hmacs, int n_elts, __be16 hmac_id)
588{
589 int found = 0;
590 int i;
591
592 for (i = 0; i < n_elts; i++) {
593 if (hmac_id == hmacs[i]) {
594 found = 1;
595 break;
596 }
597 }
598
599 return found;
600}
601
602/* See if the HMAC_ID is one that we claim as supported */
603int sctp_auth_asoc_verify_hmac_id(const struct sctp_association *asoc,
604 __be16 hmac_id)
605{
606 struct sctp_hmac_algo_param *hmacs;
607 __u16 n_elt;
608
609 if (!asoc)
610 return 0;
611
612 hmacs = (struct sctp_hmac_algo_param *)asoc->c.auth_hmacs;
613 n_elt = (ntohs(hmacs->param_hdr.length) -
614 sizeof(struct sctp_paramhdr)) >> 1;
615
616 return __sctp_auth_find_hmacid(hmacs->hmac_ids, n_elt, hmac_id);
617}
618
619
620/* Cache the default HMAC id. This to follow this text from SCTP-AUTH:
621 * Section 6.1:
622 * The receiver of a HMAC-ALGO parameter SHOULD use the first listed
623 * algorithm it supports.
624 */
625void sctp_auth_asoc_set_default_hmac(struct sctp_association *asoc,
626 struct sctp_hmac_algo_param *hmacs)
627{
628 struct sctp_endpoint *ep;
629 __u16 id;
630 int i;
631 int n_params;
632
633 /* if the default id is already set, use it */
634 if (asoc->default_hmac_id)
635 return;
636
637 n_params = (ntohs(hmacs->param_hdr.length) -
638 sizeof(struct sctp_paramhdr)) >> 1;
639 ep = asoc->ep;
640 for (i = 0; i < n_params; i++) {
641 id = ntohs(hmacs->hmac_ids[i]);
642
643 /* Check the id is in the supported range */
644 if (id > SCTP_AUTH_HMAC_ID_MAX)
645 continue;
646
647 /* If this TFM has been allocated, use this id */
648 if (ep->auth_hmacs[id]) {
649 asoc->default_hmac_id = id;
650 break;
651 }
652 }
653}
654
655
656/* Check to see if the given chunk is supposed to be authenticated */
657static int __sctp_auth_cid(enum sctp_cid chunk, struct sctp_chunks_param *param)
658{
659 unsigned short len;
660 int found = 0;
661 int i;
662
663 if (!param || param->param_hdr.length == 0)
664 return 0;
665
666 len = ntohs(param->param_hdr.length) - sizeof(struct sctp_paramhdr);
667
668 /* SCTP-AUTH, Section 3.2
669 * The chunk types for INIT, INIT-ACK, SHUTDOWN-COMPLETE and AUTH
670 * chunks MUST NOT be listed in the CHUNKS parameter. However, if
671 * a CHUNKS parameter is received then the types for INIT, INIT-ACK,
672 * SHUTDOWN-COMPLETE and AUTH chunks MUST be ignored.
673 */
674 for (i = 0; !found && i < len; i++) {
675 switch (param->chunks[i]) {
676 case SCTP_CID_INIT:
677 case SCTP_CID_INIT_ACK:
678 case SCTP_CID_SHUTDOWN_COMPLETE:
679 case SCTP_CID_AUTH:
680 break;
681
682 default:
683 if (param->chunks[i] == chunk)
684 found = 1;
685 break;
686 }
687 }
688
689 return found;
690}
691
692/* Check if peer requested that this chunk is authenticated */
693int sctp_auth_send_cid(enum sctp_cid chunk, const struct sctp_association *asoc)
694{
695 if (!asoc)
696 return 0;
697
698 if (!asoc->ep->auth_enable || !asoc->peer.auth_capable)
699 return 0;
700
701 return __sctp_auth_cid(chunk, asoc->peer.peer_chunks);
702}
703
704/* Check if we requested that peer authenticate this chunk. */
705int sctp_auth_recv_cid(enum sctp_cid chunk, const struct sctp_association *asoc)
706{
707 if (!asoc)
708 return 0;
709
710 if (!asoc->ep->auth_enable)
711 return 0;
712
713 return __sctp_auth_cid(chunk,
714 (struct sctp_chunks_param *)asoc->c.auth_chunks);
715}
716
717/* SCTP-AUTH: Section 6.2:
718 * The sender MUST calculate the MAC as described in RFC2104 [2] using
719 * the hash function H as described by the MAC Identifier and the shared
720 * association key K based on the endpoint pair shared key described by
721 * the shared key identifier. The 'data' used for the computation of
722 * the AUTH-chunk is given by the AUTH chunk with its HMAC field set to
723 * zero (as shown in Figure 6) followed by all chunks that are placed
724 * after the AUTH chunk in the SCTP packet.
725 */
726void sctp_auth_calculate_hmac(const struct sctp_association *asoc,
727 struct sk_buff *skb, struct sctp_auth_chunk *auth,
728 struct sctp_shared_key *ep_key, gfp_t gfp)
729{
730 struct sctp_auth_bytes *asoc_key;
731 struct crypto_shash *tfm;
732 __u16 key_id, hmac_id;
733 unsigned char *end;
734 int free_key = 0;
735 __u8 *digest;
736
737 /* Extract the info we need:
738 * - hmac id
739 * - key id
740 */
741 key_id = ntohs(auth->auth_hdr.shkey_id);
742 hmac_id = ntohs(auth->auth_hdr.hmac_id);
743
744 if (key_id == asoc->active_key_id)
745 asoc_key = asoc->asoc_shared_key;
746 else {
747 /* ep_key can't be NULL here */
748 asoc_key = sctp_auth_asoc_create_secret(asoc, ep_key, gfp);
749 if (!asoc_key)
750 return;
751
752 free_key = 1;
753 }
754
755 /* set up scatter list */
756 end = skb_tail_pointer(skb);
757
758 tfm = asoc->ep->auth_hmacs[hmac_id];
759
760 digest = auth->auth_hdr.hmac;
761 if (crypto_shash_setkey(tfm, &asoc_key->data[0], asoc_key->len))
762 goto free;
763
764 {
765 SHASH_DESC_ON_STACK(desc, tfm);
766
767 desc->tfm = tfm;
768 desc->flags = 0;
769 crypto_shash_digest(desc, (u8 *)auth,
770 end - (unsigned char *)auth, digest);
771 shash_desc_zero(desc);
772 }
773
774free:
775 if (free_key)
776 sctp_auth_key_put(asoc_key);
777}
778
779/* API Helpers */
780
781/* Add a chunk to the endpoint authenticated chunk list */
782int sctp_auth_ep_add_chunkid(struct sctp_endpoint *ep, __u8 chunk_id)
783{
784 struct sctp_chunks_param *p = ep->auth_chunk_list;
785 __u16 nchunks;
786 __u16 param_len;
787
788 /* If this chunk is already specified, we are done */
789 if (__sctp_auth_cid(chunk_id, p))
790 return 0;
791
792 /* Check if we can add this chunk to the array */
793 param_len = ntohs(p->param_hdr.length);
794 nchunks = param_len - sizeof(struct sctp_paramhdr);
795 if (nchunks == SCTP_NUM_CHUNK_TYPES)
796 return -EINVAL;
797
798 p->chunks[nchunks] = chunk_id;
799 p->param_hdr.length = htons(param_len + 1);
800 return 0;
801}
802
803/* Add hmac identifires to the endpoint list of supported hmac ids */
804int sctp_auth_ep_set_hmacs(struct sctp_endpoint *ep,
805 struct sctp_hmacalgo *hmacs)
806{
807 int has_sha1 = 0;
808 __u16 id;
809 int i;
810
811 /* Scan the list looking for unsupported id. Also make sure that
812 * SHA1 is specified.
813 */
814 for (i = 0; i < hmacs->shmac_num_idents; i++) {
815 id = hmacs->shmac_idents[i];
816
817 if (id > SCTP_AUTH_HMAC_ID_MAX)
818 return -EOPNOTSUPP;
819
820 if (SCTP_AUTH_HMAC_ID_SHA1 == id)
821 has_sha1 = 1;
822
823 if (!sctp_hmac_list[id].hmac_name)
824 return -EOPNOTSUPP;
825 }
826
827 if (!has_sha1)
828 return -EINVAL;
829
830 for (i = 0; i < hmacs->shmac_num_idents; i++)
831 ep->auth_hmacs_list->hmac_ids[i] =
832 htons(hmacs->shmac_idents[i]);
833 ep->auth_hmacs_list->param_hdr.length =
834 htons(sizeof(struct sctp_paramhdr) +
835 hmacs->shmac_num_idents * sizeof(__u16));
836 return 0;
837}
838
839/* Set a new shared key on either endpoint or association. If the
840 * the key with a same ID already exists, replace the key (remove the
841 * old key and add a new one).
842 */
843int sctp_auth_set_key(struct sctp_endpoint *ep,
844 struct sctp_association *asoc,
845 struct sctp_authkey *auth_key)
846{
847 struct sctp_shared_key *cur_key, *shkey;
848 struct sctp_auth_bytes *key;
849 struct list_head *sh_keys;
850 int replace = 0;
851
852 /* Try to find the given key id to see if
853 * we are doing a replace, or adding a new key
854 */
855 if (asoc)
856 sh_keys = &asoc->endpoint_shared_keys;
857 else
858 sh_keys = &ep->endpoint_shared_keys;
859
860 key_for_each(shkey, sh_keys) {
861 if (shkey->key_id == auth_key->sca_keynumber) {
862 replace = 1;
863 break;
864 }
865 }
866
867 cur_key = sctp_auth_shkey_create(auth_key->sca_keynumber, GFP_KERNEL);
868 if (!cur_key)
869 return -ENOMEM;
870
871 /* Create a new key data based on the info passed in */
872 key = sctp_auth_create_key(auth_key->sca_keylength, GFP_KERNEL);
873 if (!key) {
874 kfree(cur_key);
875 return -ENOMEM;
876 }
877
878 memcpy(key->data, &auth_key->sca_key[0], auth_key->sca_keylength);
879 cur_key->key = key;
880
881 if (replace) {
882 list_del_init(&shkey->key_list);
883 sctp_auth_shkey_release(shkey);
884 }
885 list_add(&cur_key->key_list, sh_keys);
886
887 return 0;
888}
889
890int sctp_auth_set_active_key(struct sctp_endpoint *ep,
891 struct sctp_association *asoc,
892 __u16 key_id)
893{
894 struct sctp_shared_key *key;
895 struct list_head *sh_keys;
896 int found = 0;
897
898 /* The key identifier MUST correst to an existing key */
899 if (asoc)
900 sh_keys = &asoc->endpoint_shared_keys;
901 else
902 sh_keys = &ep->endpoint_shared_keys;
903
904 key_for_each(key, sh_keys) {
905 if (key->key_id == key_id) {
906 found = 1;
907 break;
908 }
909 }
910
911 if (!found || key->deactivated)
912 return -EINVAL;
913
914 if (asoc) {
915 asoc->active_key_id = key_id;
916 sctp_auth_asoc_init_active_key(asoc, GFP_KERNEL);
917 } else
918 ep->active_key_id = key_id;
919
920 return 0;
921}
922
923int sctp_auth_del_key_id(struct sctp_endpoint *ep,
924 struct sctp_association *asoc,
925 __u16 key_id)
926{
927 struct sctp_shared_key *key;
928 struct list_head *sh_keys;
929 int found = 0;
930
931 /* The key identifier MUST NOT be the current active key
932 * The key identifier MUST correst to an existing key
933 */
934 if (asoc) {
935 if (asoc->active_key_id == key_id)
936 return -EINVAL;
937
938 sh_keys = &asoc->endpoint_shared_keys;
939 } else {
940 if (ep->active_key_id == key_id)
941 return -EINVAL;
942
943 sh_keys = &ep->endpoint_shared_keys;
944 }
945
946 key_for_each(key, sh_keys) {
947 if (key->key_id == key_id) {
948 found = 1;
949 break;
950 }
951 }
952
953 if (!found)
954 return -EINVAL;
955
956 /* Delete the shared key */
957 list_del_init(&key->key_list);
958 sctp_auth_shkey_release(key);
959
960 return 0;
961}
962
963int sctp_auth_deact_key_id(struct sctp_endpoint *ep,
964 struct sctp_association *asoc, __u16 key_id)
965{
966 struct sctp_shared_key *key;
967 struct list_head *sh_keys;
968 int found = 0;
969
970 /* The key identifier MUST NOT be the current active key
971 * The key identifier MUST correst to an existing key
972 */
973 if (asoc) {
974 if (asoc->active_key_id == key_id)
975 return -EINVAL;
976
977 sh_keys = &asoc->endpoint_shared_keys;
978 } else {
979 if (ep->active_key_id == key_id)
980 return -EINVAL;
981
982 sh_keys = &ep->endpoint_shared_keys;
983 }
984
985 key_for_each(key, sh_keys) {
986 if (key->key_id == key_id) {
987 found = 1;
988 break;
989 }
990 }
991
992 if (!found)
993 return -EINVAL;
994
995 /* refcnt == 1 and !list_empty mean it's not being used anywhere
996 * and deactivated will be set, so it's time to notify userland
997 * that this shkey can be freed.
998 */
999 if (asoc && !list_empty(&key->key_list) &&
1000 refcount_read(&key->refcnt) == 1) {
1001 struct sctp_ulpevent *ev;
1002
1003 ev = sctp_ulpevent_make_authkey(asoc, key->key_id,
1004 SCTP_AUTH_FREE_KEY, GFP_KERNEL);
1005 if (ev)
1006 asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1007 }
1008
1009 key->deactivated = 1;
1010
1011 return 0;
1012}
1// SPDX-License-Identifier: GPL-2.0-or-later
2/* SCTP kernel implementation
3 * (C) Copyright 2007 Hewlett-Packard Development Company, L.P.
4 *
5 * This file is part of the SCTP kernel implementation
6 *
7 * Please send any bug reports or fixes you make to the
8 * email address(es):
9 * lksctp developers <linux-sctp@vger.kernel.org>
10 *
11 * Written or modified by:
12 * Vlad Yasevich <vladislav.yasevich@hp.com>
13 */
14
15#include <crypto/hash.h>
16#include <linux/slab.h>
17#include <linux/types.h>
18#include <linux/scatterlist.h>
19#include <net/sctp/sctp.h>
20#include <net/sctp/auth.h>
21
22static struct sctp_hmac sctp_hmac_list[SCTP_AUTH_NUM_HMACS] = {
23 {
24 /* id 0 is reserved. as all 0 */
25 .hmac_id = SCTP_AUTH_HMAC_ID_RESERVED_0,
26 },
27 {
28 .hmac_id = SCTP_AUTH_HMAC_ID_SHA1,
29 .hmac_name = "hmac(sha1)",
30 .hmac_len = SCTP_SHA1_SIG_SIZE,
31 },
32 {
33 /* id 2 is reserved as well */
34 .hmac_id = SCTP_AUTH_HMAC_ID_RESERVED_2,
35 },
36#if IS_ENABLED(CONFIG_CRYPTO_SHA256)
37 {
38 .hmac_id = SCTP_AUTH_HMAC_ID_SHA256,
39 .hmac_name = "hmac(sha256)",
40 .hmac_len = SCTP_SHA256_SIG_SIZE,
41 }
42#endif
43};
44
45
46void sctp_auth_key_put(struct sctp_auth_bytes *key)
47{
48 if (!key)
49 return;
50
51 if (refcount_dec_and_test(&key->refcnt)) {
52 kfree_sensitive(key);
53 SCTP_DBG_OBJCNT_DEC(keys);
54 }
55}
56
57/* Create a new key structure of a given length */
58static struct sctp_auth_bytes *sctp_auth_create_key(__u32 key_len, gfp_t gfp)
59{
60 struct sctp_auth_bytes *key;
61
62 /* Verify that we are not going to overflow INT_MAX */
63 if (key_len > (INT_MAX - sizeof(struct sctp_auth_bytes)))
64 return NULL;
65
66 /* Allocate the shared key */
67 key = kmalloc(sizeof(struct sctp_auth_bytes) + key_len, gfp);
68 if (!key)
69 return NULL;
70
71 key->len = key_len;
72 refcount_set(&key->refcnt, 1);
73 SCTP_DBG_OBJCNT_INC(keys);
74
75 return key;
76}
77
78/* Create a new shared key container with a give key id */
79struct sctp_shared_key *sctp_auth_shkey_create(__u16 key_id, gfp_t gfp)
80{
81 struct sctp_shared_key *new;
82
83 /* Allocate the shared key container */
84 new = kzalloc(sizeof(struct sctp_shared_key), gfp);
85 if (!new)
86 return NULL;
87
88 INIT_LIST_HEAD(&new->key_list);
89 refcount_set(&new->refcnt, 1);
90 new->key_id = key_id;
91
92 return new;
93}
94
95/* Free the shared key structure */
96static void sctp_auth_shkey_destroy(struct sctp_shared_key *sh_key)
97{
98 BUG_ON(!list_empty(&sh_key->key_list));
99 sctp_auth_key_put(sh_key->key);
100 sh_key->key = NULL;
101 kfree(sh_key);
102}
103
104void sctp_auth_shkey_release(struct sctp_shared_key *sh_key)
105{
106 if (refcount_dec_and_test(&sh_key->refcnt))
107 sctp_auth_shkey_destroy(sh_key);
108}
109
110void sctp_auth_shkey_hold(struct sctp_shared_key *sh_key)
111{
112 refcount_inc(&sh_key->refcnt);
113}
114
115/* Destroy the entire key list. This is done during the
116 * associon and endpoint free process.
117 */
118void sctp_auth_destroy_keys(struct list_head *keys)
119{
120 struct sctp_shared_key *ep_key;
121 struct sctp_shared_key *tmp;
122
123 if (list_empty(keys))
124 return;
125
126 key_for_each_safe(ep_key, tmp, keys) {
127 list_del_init(&ep_key->key_list);
128 sctp_auth_shkey_release(ep_key);
129 }
130}
131
132/* Compare two byte vectors as numbers. Return values
133 * are:
134 * 0 - vectors are equal
135 * < 0 - vector 1 is smaller than vector2
136 * > 0 - vector 1 is greater than vector2
137 *
138 * Algorithm is:
139 * This is performed by selecting the numerically smaller key vector...
140 * If the key vectors are equal as numbers but differ in length ...
141 * the shorter vector is considered smaller
142 *
143 * Examples (with small values):
144 * 000123456789 > 123456789 (first number is longer)
145 * 000123456789 < 234567891 (second number is larger numerically)
146 * 123456789 > 2345678 (first number is both larger & longer)
147 */
148static int sctp_auth_compare_vectors(struct sctp_auth_bytes *vector1,
149 struct sctp_auth_bytes *vector2)
150{
151 int diff;
152 int i;
153 const __u8 *longer;
154
155 diff = vector1->len - vector2->len;
156 if (diff) {
157 longer = (diff > 0) ? vector1->data : vector2->data;
158
159 /* Check to see if the longer number is
160 * lead-zero padded. If it is not, it
161 * is automatically larger numerically.
162 */
163 for (i = 0; i < abs(diff); i++) {
164 if (longer[i] != 0)
165 return diff;
166 }
167 }
168
169 /* lengths are the same, compare numbers */
170 return memcmp(vector1->data, vector2->data, vector1->len);
171}
172
173/*
174 * Create a key vector as described in SCTP-AUTH, Section 6.1
175 * The RANDOM parameter, the CHUNKS parameter and the HMAC-ALGO
176 * parameter sent by each endpoint are concatenated as byte vectors.
177 * These parameters include the parameter type, parameter length, and
178 * the parameter value, but padding is omitted; all padding MUST be
179 * removed from this concatenation before proceeding with further
180 * computation of keys. Parameters which were not sent are simply
181 * omitted from the concatenation process. The resulting two vectors
182 * are called the two key vectors.
183 */
184static struct sctp_auth_bytes *sctp_auth_make_key_vector(
185 struct sctp_random_param *random,
186 struct sctp_chunks_param *chunks,
187 struct sctp_hmac_algo_param *hmacs,
188 gfp_t gfp)
189{
190 struct sctp_auth_bytes *new;
191 __u32 len;
192 __u32 offset = 0;
193 __u16 random_len, hmacs_len, chunks_len = 0;
194
195 random_len = ntohs(random->param_hdr.length);
196 hmacs_len = ntohs(hmacs->param_hdr.length);
197 if (chunks)
198 chunks_len = ntohs(chunks->param_hdr.length);
199
200 len = random_len + hmacs_len + chunks_len;
201
202 new = sctp_auth_create_key(len, gfp);
203 if (!new)
204 return NULL;
205
206 memcpy(new->data, random, random_len);
207 offset += random_len;
208
209 if (chunks) {
210 memcpy(new->data + offset, chunks, chunks_len);
211 offset += chunks_len;
212 }
213
214 memcpy(new->data + offset, hmacs, hmacs_len);
215
216 return new;
217}
218
219
220/* Make a key vector based on our local parameters */
221static struct sctp_auth_bytes *sctp_auth_make_local_vector(
222 const struct sctp_association *asoc,
223 gfp_t gfp)
224{
225 return sctp_auth_make_key_vector(
226 (struct sctp_random_param *)asoc->c.auth_random,
227 (struct sctp_chunks_param *)asoc->c.auth_chunks,
228 (struct sctp_hmac_algo_param *)asoc->c.auth_hmacs, gfp);
229}
230
231/* Make a key vector based on peer's parameters */
232static struct sctp_auth_bytes *sctp_auth_make_peer_vector(
233 const struct sctp_association *asoc,
234 gfp_t gfp)
235{
236 return sctp_auth_make_key_vector(asoc->peer.peer_random,
237 asoc->peer.peer_chunks,
238 asoc->peer.peer_hmacs,
239 gfp);
240}
241
242
243/* Set the value of the association shared key base on the parameters
244 * given. The algorithm is:
245 * From the endpoint pair shared keys and the key vectors the
246 * association shared keys are computed. This is performed by selecting
247 * the numerically smaller key vector and concatenating it to the
248 * endpoint pair shared key, and then concatenating the numerically
249 * larger key vector to that. The result of the concatenation is the
250 * association shared key.
251 */
252static struct sctp_auth_bytes *sctp_auth_asoc_set_secret(
253 struct sctp_shared_key *ep_key,
254 struct sctp_auth_bytes *first_vector,
255 struct sctp_auth_bytes *last_vector,
256 gfp_t gfp)
257{
258 struct sctp_auth_bytes *secret;
259 __u32 offset = 0;
260 __u32 auth_len;
261
262 auth_len = first_vector->len + last_vector->len;
263 if (ep_key->key)
264 auth_len += ep_key->key->len;
265
266 secret = sctp_auth_create_key(auth_len, gfp);
267 if (!secret)
268 return NULL;
269
270 if (ep_key->key) {
271 memcpy(secret->data, ep_key->key->data, ep_key->key->len);
272 offset += ep_key->key->len;
273 }
274
275 memcpy(secret->data + offset, first_vector->data, first_vector->len);
276 offset += first_vector->len;
277
278 memcpy(secret->data + offset, last_vector->data, last_vector->len);
279
280 return secret;
281}
282
283/* Create an association shared key. Follow the algorithm
284 * described in SCTP-AUTH, Section 6.1
285 */
286static struct sctp_auth_bytes *sctp_auth_asoc_create_secret(
287 const struct sctp_association *asoc,
288 struct sctp_shared_key *ep_key,
289 gfp_t gfp)
290{
291 struct sctp_auth_bytes *local_key_vector;
292 struct sctp_auth_bytes *peer_key_vector;
293 struct sctp_auth_bytes *first_vector,
294 *last_vector;
295 struct sctp_auth_bytes *secret = NULL;
296 int cmp;
297
298
299 /* Now we need to build the key vectors
300 * SCTP-AUTH , Section 6.1
301 * The RANDOM parameter, the CHUNKS parameter and the HMAC-ALGO
302 * parameter sent by each endpoint are concatenated as byte vectors.
303 * These parameters include the parameter type, parameter length, and
304 * the parameter value, but padding is omitted; all padding MUST be
305 * removed from this concatenation before proceeding with further
306 * computation of keys. Parameters which were not sent are simply
307 * omitted from the concatenation process. The resulting two vectors
308 * are called the two key vectors.
309 */
310
311 local_key_vector = sctp_auth_make_local_vector(asoc, gfp);
312 peer_key_vector = sctp_auth_make_peer_vector(asoc, gfp);
313
314 if (!peer_key_vector || !local_key_vector)
315 goto out;
316
317 /* Figure out the order in which the key_vectors will be
318 * added to the endpoint shared key.
319 * SCTP-AUTH, Section 6.1:
320 * This is performed by selecting the numerically smaller key
321 * vector and concatenating it to the endpoint pair shared
322 * key, and then concatenating the numerically larger key
323 * vector to that. If the key vectors are equal as numbers
324 * but differ in length, then the concatenation order is the
325 * endpoint shared key, followed by the shorter key vector,
326 * followed by the longer key vector. Otherwise, the key
327 * vectors are identical, and may be concatenated to the
328 * endpoint pair key in any order.
329 */
330 cmp = sctp_auth_compare_vectors(local_key_vector,
331 peer_key_vector);
332 if (cmp < 0) {
333 first_vector = local_key_vector;
334 last_vector = peer_key_vector;
335 } else {
336 first_vector = peer_key_vector;
337 last_vector = local_key_vector;
338 }
339
340 secret = sctp_auth_asoc_set_secret(ep_key, first_vector, last_vector,
341 gfp);
342out:
343 sctp_auth_key_put(local_key_vector);
344 sctp_auth_key_put(peer_key_vector);
345
346 return secret;
347}
348
349/*
350 * Populate the association overlay list with the list
351 * from the endpoint.
352 */
353int sctp_auth_asoc_copy_shkeys(const struct sctp_endpoint *ep,
354 struct sctp_association *asoc,
355 gfp_t gfp)
356{
357 struct sctp_shared_key *sh_key;
358 struct sctp_shared_key *new;
359
360 BUG_ON(!list_empty(&asoc->endpoint_shared_keys));
361
362 key_for_each(sh_key, &ep->endpoint_shared_keys) {
363 new = sctp_auth_shkey_create(sh_key->key_id, gfp);
364 if (!new)
365 goto nomem;
366
367 new->key = sh_key->key;
368 sctp_auth_key_hold(new->key);
369 list_add(&new->key_list, &asoc->endpoint_shared_keys);
370 }
371
372 return 0;
373
374nomem:
375 sctp_auth_destroy_keys(&asoc->endpoint_shared_keys);
376 return -ENOMEM;
377}
378
379
380/* Public interface to create the association shared key.
381 * See code above for the algorithm.
382 */
383int sctp_auth_asoc_init_active_key(struct sctp_association *asoc, gfp_t gfp)
384{
385 struct sctp_auth_bytes *secret;
386 struct sctp_shared_key *ep_key;
387 struct sctp_chunk *chunk;
388
389 /* If we don't support AUTH, or peer is not capable
390 * we don't need to do anything.
391 */
392 if (!asoc->peer.auth_capable)
393 return 0;
394
395 /* If the key_id is non-zero and we couldn't find an
396 * endpoint pair shared key, we can't compute the
397 * secret.
398 * For key_id 0, endpoint pair shared key is a NULL key.
399 */
400 ep_key = sctp_auth_get_shkey(asoc, asoc->active_key_id);
401 BUG_ON(!ep_key);
402
403 secret = sctp_auth_asoc_create_secret(asoc, ep_key, gfp);
404 if (!secret)
405 return -ENOMEM;
406
407 sctp_auth_key_put(asoc->asoc_shared_key);
408 asoc->asoc_shared_key = secret;
409 asoc->shkey = ep_key;
410
411 /* Update send queue in case any chunk already in there now
412 * needs authenticating
413 */
414 list_for_each_entry(chunk, &asoc->outqueue.out_chunk_list, list) {
415 if (sctp_auth_send_cid(chunk->chunk_hdr->type, asoc)) {
416 chunk->auth = 1;
417 if (!chunk->shkey) {
418 chunk->shkey = asoc->shkey;
419 sctp_auth_shkey_hold(chunk->shkey);
420 }
421 }
422 }
423
424 return 0;
425}
426
427
428/* Find the endpoint pair shared key based on the key_id */
429struct sctp_shared_key *sctp_auth_get_shkey(
430 const struct sctp_association *asoc,
431 __u16 key_id)
432{
433 struct sctp_shared_key *key;
434
435 /* First search associations set of endpoint pair shared keys */
436 key_for_each(key, &asoc->endpoint_shared_keys) {
437 if (key->key_id == key_id) {
438 if (!key->deactivated)
439 return key;
440 break;
441 }
442 }
443
444 return NULL;
445}
446
447/*
448 * Initialize all the possible digest transforms that we can use. Right
449 * now, the supported digests are SHA1 and SHA256. We do this here once
450 * because of the restrictiong that transforms may only be allocated in
451 * user context. This forces us to pre-allocated all possible transforms
452 * at the endpoint init time.
453 */
454int sctp_auth_init_hmacs(struct sctp_endpoint *ep, gfp_t gfp)
455{
456 struct crypto_shash *tfm = NULL;
457 __u16 id;
458
459 /* If the transforms are already allocated, we are done */
460 if (ep->auth_hmacs)
461 return 0;
462
463 /* Allocated the array of pointers to transorms */
464 ep->auth_hmacs = kcalloc(SCTP_AUTH_NUM_HMACS,
465 sizeof(struct crypto_shash *),
466 gfp);
467 if (!ep->auth_hmacs)
468 return -ENOMEM;
469
470 for (id = 0; id < SCTP_AUTH_NUM_HMACS; id++) {
471
472 /* See is we support the id. Supported IDs have name and
473 * length fields set, so that we can allocated and use
474 * them. We can safely just check for name, for without the
475 * name, we can't allocate the TFM.
476 */
477 if (!sctp_hmac_list[id].hmac_name)
478 continue;
479
480 /* If this TFM has been allocated, we are all set */
481 if (ep->auth_hmacs[id])
482 continue;
483
484 /* Allocate the ID */
485 tfm = crypto_alloc_shash(sctp_hmac_list[id].hmac_name, 0, 0);
486 if (IS_ERR(tfm))
487 goto out_err;
488
489 ep->auth_hmacs[id] = tfm;
490 }
491
492 return 0;
493
494out_err:
495 /* Clean up any successful allocations */
496 sctp_auth_destroy_hmacs(ep->auth_hmacs);
497 ep->auth_hmacs = NULL;
498 return -ENOMEM;
499}
500
501/* Destroy the hmac tfm array */
502void sctp_auth_destroy_hmacs(struct crypto_shash *auth_hmacs[])
503{
504 int i;
505
506 if (!auth_hmacs)
507 return;
508
509 for (i = 0; i < SCTP_AUTH_NUM_HMACS; i++) {
510 crypto_free_shash(auth_hmacs[i]);
511 }
512 kfree(auth_hmacs);
513}
514
515
516struct sctp_hmac *sctp_auth_get_hmac(__u16 hmac_id)
517{
518 return &sctp_hmac_list[hmac_id];
519}
520
521/* Get an hmac description information that we can use to build
522 * the AUTH chunk
523 */
524struct sctp_hmac *sctp_auth_asoc_get_hmac(const struct sctp_association *asoc)
525{
526 struct sctp_hmac_algo_param *hmacs;
527 __u16 n_elt;
528 __u16 id = 0;
529 int i;
530
531 /* If we have a default entry, use it */
532 if (asoc->default_hmac_id)
533 return &sctp_hmac_list[asoc->default_hmac_id];
534
535 /* Since we do not have a default entry, find the first entry
536 * we support and return that. Do not cache that id.
537 */
538 hmacs = asoc->peer.peer_hmacs;
539 if (!hmacs)
540 return NULL;
541
542 n_elt = (ntohs(hmacs->param_hdr.length) -
543 sizeof(struct sctp_paramhdr)) >> 1;
544 for (i = 0; i < n_elt; i++) {
545 id = ntohs(hmacs->hmac_ids[i]);
546
547 /* Check the id is in the supported range. And
548 * see if we support the id. Supported IDs have name and
549 * length fields set, so that we can allocate and use
550 * them. We can safely just check for name, for without the
551 * name, we can't allocate the TFM.
552 */
553 if (id > SCTP_AUTH_HMAC_ID_MAX ||
554 !sctp_hmac_list[id].hmac_name) {
555 id = 0;
556 continue;
557 }
558
559 break;
560 }
561
562 if (id == 0)
563 return NULL;
564
565 return &sctp_hmac_list[id];
566}
567
568static int __sctp_auth_find_hmacid(__be16 *hmacs, int n_elts, __be16 hmac_id)
569{
570 int found = 0;
571 int i;
572
573 for (i = 0; i < n_elts; i++) {
574 if (hmac_id == hmacs[i]) {
575 found = 1;
576 break;
577 }
578 }
579
580 return found;
581}
582
583/* See if the HMAC_ID is one that we claim as supported */
584int sctp_auth_asoc_verify_hmac_id(const struct sctp_association *asoc,
585 __be16 hmac_id)
586{
587 struct sctp_hmac_algo_param *hmacs;
588 __u16 n_elt;
589
590 if (!asoc)
591 return 0;
592
593 hmacs = (struct sctp_hmac_algo_param *)asoc->c.auth_hmacs;
594 n_elt = (ntohs(hmacs->param_hdr.length) -
595 sizeof(struct sctp_paramhdr)) >> 1;
596
597 return __sctp_auth_find_hmacid(hmacs->hmac_ids, n_elt, hmac_id);
598}
599
600
601/* Cache the default HMAC id. This to follow this text from SCTP-AUTH:
602 * Section 6.1:
603 * The receiver of a HMAC-ALGO parameter SHOULD use the first listed
604 * algorithm it supports.
605 */
606void sctp_auth_asoc_set_default_hmac(struct sctp_association *asoc,
607 struct sctp_hmac_algo_param *hmacs)
608{
609 struct sctp_endpoint *ep;
610 __u16 id;
611 int i;
612 int n_params;
613
614 /* if the default id is already set, use it */
615 if (asoc->default_hmac_id)
616 return;
617
618 n_params = (ntohs(hmacs->param_hdr.length) -
619 sizeof(struct sctp_paramhdr)) >> 1;
620 ep = asoc->ep;
621 for (i = 0; i < n_params; i++) {
622 id = ntohs(hmacs->hmac_ids[i]);
623
624 /* Check the id is in the supported range */
625 if (id > SCTP_AUTH_HMAC_ID_MAX)
626 continue;
627
628 /* If this TFM has been allocated, use this id */
629 if (ep->auth_hmacs[id]) {
630 asoc->default_hmac_id = id;
631 break;
632 }
633 }
634}
635
636
637/* Check to see if the given chunk is supposed to be authenticated */
638static int __sctp_auth_cid(enum sctp_cid chunk, struct sctp_chunks_param *param)
639{
640 unsigned short len;
641 int found = 0;
642 int i;
643
644 if (!param || param->param_hdr.length == 0)
645 return 0;
646
647 len = ntohs(param->param_hdr.length) - sizeof(struct sctp_paramhdr);
648
649 /* SCTP-AUTH, Section 3.2
650 * The chunk types for INIT, INIT-ACK, SHUTDOWN-COMPLETE and AUTH
651 * chunks MUST NOT be listed in the CHUNKS parameter. However, if
652 * a CHUNKS parameter is received then the types for INIT, INIT-ACK,
653 * SHUTDOWN-COMPLETE and AUTH chunks MUST be ignored.
654 */
655 for (i = 0; !found && i < len; i++) {
656 switch (param->chunks[i]) {
657 case SCTP_CID_INIT:
658 case SCTP_CID_INIT_ACK:
659 case SCTP_CID_SHUTDOWN_COMPLETE:
660 case SCTP_CID_AUTH:
661 break;
662
663 default:
664 if (param->chunks[i] == chunk)
665 found = 1;
666 break;
667 }
668 }
669
670 return found;
671}
672
673/* Check if peer requested that this chunk is authenticated */
674int sctp_auth_send_cid(enum sctp_cid chunk, const struct sctp_association *asoc)
675{
676 if (!asoc)
677 return 0;
678
679 if (!asoc->peer.auth_capable)
680 return 0;
681
682 return __sctp_auth_cid(chunk, asoc->peer.peer_chunks);
683}
684
685/* Check if we requested that peer authenticate this chunk. */
686int sctp_auth_recv_cid(enum sctp_cid chunk, const struct sctp_association *asoc)
687{
688 if (!asoc)
689 return 0;
690
691 if (!asoc->peer.auth_capable)
692 return 0;
693
694 return __sctp_auth_cid(chunk,
695 (struct sctp_chunks_param *)asoc->c.auth_chunks);
696}
697
698/* SCTP-AUTH: Section 6.2:
699 * The sender MUST calculate the MAC as described in RFC2104 [2] using
700 * the hash function H as described by the MAC Identifier and the shared
701 * association key K based on the endpoint pair shared key described by
702 * the shared key identifier. The 'data' used for the computation of
703 * the AUTH-chunk is given by the AUTH chunk with its HMAC field set to
704 * zero (as shown in Figure 6) followed by all chunks that are placed
705 * after the AUTH chunk in the SCTP packet.
706 */
707void sctp_auth_calculate_hmac(const struct sctp_association *asoc,
708 struct sk_buff *skb, struct sctp_auth_chunk *auth,
709 struct sctp_shared_key *ep_key, gfp_t gfp)
710{
711 struct sctp_auth_bytes *asoc_key;
712 struct crypto_shash *tfm;
713 __u16 key_id, hmac_id;
714 unsigned char *end;
715 int free_key = 0;
716 __u8 *digest;
717
718 /* Extract the info we need:
719 * - hmac id
720 * - key id
721 */
722 key_id = ntohs(auth->auth_hdr.shkey_id);
723 hmac_id = ntohs(auth->auth_hdr.hmac_id);
724
725 if (key_id == asoc->active_key_id)
726 asoc_key = asoc->asoc_shared_key;
727 else {
728 /* ep_key can't be NULL here */
729 asoc_key = sctp_auth_asoc_create_secret(asoc, ep_key, gfp);
730 if (!asoc_key)
731 return;
732
733 free_key = 1;
734 }
735
736 /* set up scatter list */
737 end = skb_tail_pointer(skb);
738
739 tfm = asoc->ep->auth_hmacs[hmac_id];
740
741 digest = (u8 *)(&auth->auth_hdr + 1);
742 if (crypto_shash_setkey(tfm, &asoc_key->data[0], asoc_key->len))
743 goto free;
744
745 crypto_shash_tfm_digest(tfm, (u8 *)auth, end - (unsigned char *)auth,
746 digest);
747
748free:
749 if (free_key)
750 sctp_auth_key_put(asoc_key);
751}
752
753/* API Helpers */
754
755/* Add a chunk to the endpoint authenticated chunk list */
756int sctp_auth_ep_add_chunkid(struct sctp_endpoint *ep, __u8 chunk_id)
757{
758 struct sctp_chunks_param *p = ep->auth_chunk_list;
759 __u16 nchunks;
760 __u16 param_len;
761
762 /* If this chunk is already specified, we are done */
763 if (__sctp_auth_cid(chunk_id, p))
764 return 0;
765
766 /* Check if we can add this chunk to the array */
767 param_len = ntohs(p->param_hdr.length);
768 nchunks = param_len - sizeof(struct sctp_paramhdr);
769 if (nchunks == SCTP_NUM_CHUNK_TYPES)
770 return -EINVAL;
771
772 p->chunks[nchunks] = chunk_id;
773 p->param_hdr.length = htons(param_len + 1);
774 return 0;
775}
776
777/* Add hmac identifires to the endpoint list of supported hmac ids */
778int sctp_auth_ep_set_hmacs(struct sctp_endpoint *ep,
779 struct sctp_hmacalgo *hmacs)
780{
781 int has_sha1 = 0;
782 __u16 id;
783 int i;
784
785 /* Scan the list looking for unsupported id. Also make sure that
786 * SHA1 is specified.
787 */
788 for (i = 0; i < hmacs->shmac_num_idents; i++) {
789 id = hmacs->shmac_idents[i];
790
791 if (id > SCTP_AUTH_HMAC_ID_MAX)
792 return -EOPNOTSUPP;
793
794 if (SCTP_AUTH_HMAC_ID_SHA1 == id)
795 has_sha1 = 1;
796
797 if (!sctp_hmac_list[id].hmac_name)
798 return -EOPNOTSUPP;
799 }
800
801 if (!has_sha1)
802 return -EINVAL;
803
804 for (i = 0; i < hmacs->shmac_num_idents; i++)
805 ep->auth_hmacs_list->hmac_ids[i] =
806 htons(hmacs->shmac_idents[i]);
807 ep->auth_hmacs_list->param_hdr.length =
808 htons(sizeof(struct sctp_paramhdr) +
809 hmacs->shmac_num_idents * sizeof(__u16));
810 return 0;
811}
812
813/* Set a new shared key on either endpoint or association. If the
814 * key with a same ID already exists, replace the key (remove the
815 * old key and add a new one).
816 */
817int sctp_auth_set_key(struct sctp_endpoint *ep,
818 struct sctp_association *asoc,
819 struct sctp_authkey *auth_key)
820{
821 struct sctp_shared_key *cur_key, *shkey;
822 struct sctp_auth_bytes *key;
823 struct list_head *sh_keys;
824 int replace = 0;
825
826 /* Try to find the given key id to see if
827 * we are doing a replace, or adding a new key
828 */
829 if (asoc) {
830 if (!asoc->peer.auth_capable)
831 return -EACCES;
832 sh_keys = &asoc->endpoint_shared_keys;
833 } else {
834 if (!ep->auth_enable)
835 return -EACCES;
836 sh_keys = &ep->endpoint_shared_keys;
837 }
838
839 key_for_each(shkey, sh_keys) {
840 if (shkey->key_id == auth_key->sca_keynumber) {
841 replace = 1;
842 break;
843 }
844 }
845
846 cur_key = sctp_auth_shkey_create(auth_key->sca_keynumber, GFP_KERNEL);
847 if (!cur_key)
848 return -ENOMEM;
849
850 /* Create a new key data based on the info passed in */
851 key = sctp_auth_create_key(auth_key->sca_keylength, GFP_KERNEL);
852 if (!key) {
853 kfree(cur_key);
854 return -ENOMEM;
855 }
856
857 memcpy(key->data, &auth_key->sca_key[0], auth_key->sca_keylength);
858 cur_key->key = key;
859
860 if (!replace) {
861 list_add(&cur_key->key_list, sh_keys);
862 return 0;
863 }
864
865 list_del_init(&shkey->key_list);
866 list_add(&cur_key->key_list, sh_keys);
867
868 if (asoc && asoc->active_key_id == auth_key->sca_keynumber &&
869 sctp_auth_asoc_init_active_key(asoc, GFP_KERNEL)) {
870 list_del_init(&cur_key->key_list);
871 sctp_auth_shkey_release(cur_key);
872 list_add(&shkey->key_list, sh_keys);
873 return -ENOMEM;
874 }
875
876 sctp_auth_shkey_release(shkey);
877 return 0;
878}
879
880int sctp_auth_set_active_key(struct sctp_endpoint *ep,
881 struct sctp_association *asoc,
882 __u16 key_id)
883{
884 struct sctp_shared_key *key;
885 struct list_head *sh_keys;
886 int found = 0;
887
888 /* The key identifier MUST correst to an existing key */
889 if (asoc) {
890 if (!asoc->peer.auth_capable)
891 return -EACCES;
892 sh_keys = &asoc->endpoint_shared_keys;
893 } else {
894 if (!ep->auth_enable)
895 return -EACCES;
896 sh_keys = &ep->endpoint_shared_keys;
897 }
898
899 key_for_each(key, sh_keys) {
900 if (key->key_id == key_id) {
901 found = 1;
902 break;
903 }
904 }
905
906 if (!found || key->deactivated)
907 return -EINVAL;
908
909 if (asoc) {
910 __u16 active_key_id = asoc->active_key_id;
911
912 asoc->active_key_id = key_id;
913 if (sctp_auth_asoc_init_active_key(asoc, GFP_KERNEL)) {
914 asoc->active_key_id = active_key_id;
915 return -ENOMEM;
916 }
917 } else
918 ep->active_key_id = key_id;
919
920 return 0;
921}
922
923int sctp_auth_del_key_id(struct sctp_endpoint *ep,
924 struct sctp_association *asoc,
925 __u16 key_id)
926{
927 struct sctp_shared_key *key;
928 struct list_head *sh_keys;
929 int found = 0;
930
931 /* The key identifier MUST NOT be the current active key
932 * The key identifier MUST correst to an existing key
933 */
934 if (asoc) {
935 if (!asoc->peer.auth_capable)
936 return -EACCES;
937 if (asoc->active_key_id == key_id)
938 return -EINVAL;
939
940 sh_keys = &asoc->endpoint_shared_keys;
941 } else {
942 if (!ep->auth_enable)
943 return -EACCES;
944 if (ep->active_key_id == key_id)
945 return -EINVAL;
946
947 sh_keys = &ep->endpoint_shared_keys;
948 }
949
950 key_for_each(key, sh_keys) {
951 if (key->key_id == key_id) {
952 found = 1;
953 break;
954 }
955 }
956
957 if (!found)
958 return -EINVAL;
959
960 /* Delete the shared key */
961 list_del_init(&key->key_list);
962 sctp_auth_shkey_release(key);
963
964 return 0;
965}
966
967int sctp_auth_deact_key_id(struct sctp_endpoint *ep,
968 struct sctp_association *asoc, __u16 key_id)
969{
970 struct sctp_shared_key *key;
971 struct list_head *sh_keys;
972 int found = 0;
973
974 /* The key identifier MUST NOT be the current active key
975 * The key identifier MUST correst to an existing key
976 */
977 if (asoc) {
978 if (!asoc->peer.auth_capable)
979 return -EACCES;
980 if (asoc->active_key_id == key_id)
981 return -EINVAL;
982
983 sh_keys = &asoc->endpoint_shared_keys;
984 } else {
985 if (!ep->auth_enable)
986 return -EACCES;
987 if (ep->active_key_id == key_id)
988 return -EINVAL;
989
990 sh_keys = &ep->endpoint_shared_keys;
991 }
992
993 key_for_each(key, sh_keys) {
994 if (key->key_id == key_id) {
995 found = 1;
996 break;
997 }
998 }
999
1000 if (!found)
1001 return -EINVAL;
1002
1003 /* refcnt == 1 and !list_empty mean it's not being used anywhere
1004 * and deactivated will be set, so it's time to notify userland
1005 * that this shkey can be freed.
1006 */
1007 if (asoc && !list_empty(&key->key_list) &&
1008 refcount_read(&key->refcnt) == 1) {
1009 struct sctp_ulpevent *ev;
1010
1011 ev = sctp_ulpevent_make_authkey(asoc, key->key_id,
1012 SCTP_AUTH_FREE_KEY, GFP_KERNEL);
1013 if (ev)
1014 asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
1015 }
1016
1017 key->deactivated = 1;
1018
1019 return 0;
1020}
1021
1022int sctp_auth_init(struct sctp_endpoint *ep, gfp_t gfp)
1023{
1024 int err = -ENOMEM;
1025
1026 /* Allocate space for HMACS and CHUNKS authentication
1027 * variables. There are arrays that we encode directly
1028 * into parameters to make the rest of the operations easier.
1029 */
1030 if (!ep->auth_hmacs_list) {
1031 struct sctp_hmac_algo_param *auth_hmacs;
1032
1033 auth_hmacs = kzalloc(struct_size(auth_hmacs, hmac_ids,
1034 SCTP_AUTH_NUM_HMACS), gfp);
1035 if (!auth_hmacs)
1036 goto nomem;
1037 /* Initialize the HMACS parameter.
1038 * SCTP-AUTH: Section 3.3
1039 * Every endpoint supporting SCTP chunk authentication MUST
1040 * support the HMAC based on the SHA-1 algorithm.
1041 */
1042 auth_hmacs->param_hdr.type = SCTP_PARAM_HMAC_ALGO;
1043 auth_hmacs->param_hdr.length =
1044 htons(sizeof(struct sctp_paramhdr) + 2);
1045 auth_hmacs->hmac_ids[0] = htons(SCTP_AUTH_HMAC_ID_SHA1);
1046 ep->auth_hmacs_list = auth_hmacs;
1047 }
1048
1049 if (!ep->auth_chunk_list) {
1050 struct sctp_chunks_param *auth_chunks;
1051
1052 auth_chunks = kzalloc(sizeof(*auth_chunks) +
1053 SCTP_NUM_CHUNK_TYPES, gfp);
1054 if (!auth_chunks)
1055 goto nomem;
1056 /* Initialize the CHUNKS parameter */
1057 auth_chunks->param_hdr.type = SCTP_PARAM_CHUNKS;
1058 auth_chunks->param_hdr.length =
1059 htons(sizeof(struct sctp_paramhdr));
1060 ep->auth_chunk_list = auth_chunks;
1061 }
1062
1063 /* Allocate and initialize transorms arrays for supported
1064 * HMACs.
1065 */
1066 err = sctp_auth_init_hmacs(ep, gfp);
1067 if (err)
1068 goto nomem;
1069
1070 return 0;
1071
1072nomem:
1073 /* Free all allocations */
1074 kfree(ep->auth_hmacs_list);
1075 kfree(ep->auth_chunk_list);
1076 ep->auth_hmacs_list = NULL;
1077 ep->auth_chunk_list = NULL;
1078 return err;
1079}
1080
1081void sctp_auth_free(struct sctp_endpoint *ep)
1082{
1083 kfree(ep->auth_hmacs_list);
1084 kfree(ep->auth_chunk_list);
1085 ep->auth_hmacs_list = NULL;
1086 ep->auth_chunk_list = NULL;
1087 sctp_auth_destroy_hmacs(ep->auth_hmacs);
1088 ep->auth_hmacs = NULL;
1089}